Bidi: add Bidi.invert()

frontend/ui/bidi.lua

@@ -43,6 +43,7 @@ local _ = require("gettext")
 local Bidi = {
     _mirrored_ui_layout = false,
     _rtl_ui_text = false,
+    _inverted = false,
 }
 
 -- Setup UI mirroring and RTL text for UI language
@@ -126,6 +127,22 @@ function Bidi.mirroredUILayout()
     return Bidi._mirrored_ui_layout
 end
 
+-- This fuction can be used by document widgets to temporarily match a widget
+-- to the document page turn direction instead of the UI layout direction.
+function Bidi.invert()
+    if G_reader_settings:isTrue("invert_ui_layout_mirroring") and not Bidi._inverted then
+        Bidi._mirrored_ui_layout = not Bidi._mirrored_ui_layout
+        Bidi._inverted = true
+    end
+end
+
+function Bidi.resetInvert()
+    if Bidi._inverted then
+        Bidi._mirrored_ui_layout = not Bidi._mirrored_ui_layout
+        Bidi._inverted = false
+    end
+end
+
 -- This function might only be useful in some rare cases (RTL text
 -- is handled directly by TextWidget and TextBoxWidget)
 function Bidi.rtlUIText()

frontend/ui/elements/page_turns.lua

@@ -122,6 +122,21 @@ local PageTurns = {
                     end,
                 })
             end,
+        },
+        {
+            text = _("Also invert document-related dialogs"),
+            checked_func = function()
+                return G_reader_settings:isTrue("invert_ui_layout_mirroring")
+            end,
+            enabled_func = function()
+                return ReaderUI.instance.view.inverse_reading_order
+            end,
+            callback = function()
+                G_reader_settings:flipNilOrFalse("invert_ui_layout_mirroring")
+            end,
+            help_text = _([[
+When enabled the UI direction for the Table of Contents, Book Map, and Page Browser dialogs will follow the page turn direction instead of the default UI direction.]]),
+            separator = true,
         }
     }
 }